There is no causative / curative therapy. Symptomatic medical treatments are focussing on symptoms caused by orthopaedic, dental or cardiac problems. Regarding perioperative / anesthesiological management, recommendations for medical professionals are published at OrphanAnesthesia.

Treatment for individuals with Dandy–Walker Syndrome generally consists of treating the associated problems, if needed.

A special tube (shunt) to reduce intracranial pressure may be placed inside the skull to control swelling. Endoscopic third ventriculostomy is also an option.

Treatment may also consist of various therapies such as occupational therapy, physiotherapy, speech therapy or specialized education. Services of a teacher of students with blindness/visual impairment may be helpful if the eyes are affected.

Because this malformation is rare and there are extremely few individuals living with this condition, treatment is limited. Treatment consists of carefully managing the condition in a controlled manner. Proceeding with a bone graft when the child reaches school age is also recommended.

There is no cure for this condition. Treatment is supportive and varies depending on how symptoms present and their severity. Some degree of developmental delay is expected in almost all cases of M-CM, so evaluation for early intervention or special education programs is appropriate. Rare cases have been reported with no discernible delay in academic or school abilities.

Physical therapy and orthopedic bracing can help young children with gross motor development. Occupational therapy or speech therapy may also assist with developmental delays. Attention from an orthopedic surgeon may be required for leg length discrepancy due to hemihyperplasia.

Children with hemihyperplasia are thought to have an elevated risk for certain types of cancers. Recently published management guidelines recommend regular abdominal ultrasounds up to age eight to detect Wilms' tumor. AFP testing to detect liver cancer is not recommended as there have been no reported cases of hepatoblastoma in M-CM patients.

Congenital abnormalities in the brain and progressive brain overgrowth can result in a variety of neurological problems that may require intervention. These include hydrocephalus, cerebellar tonsillar herniation (Chiari I), seizures and syringomyelia. These complications are not usually congenital, they develop over time often presenting complications in late infancy or early childhood, though they can become problems even later. Baseline brain and spinal cord MRI imaging with repeat scans at regular intervals is often prescribed to monitor the changes that result from progressive brain overgrowth.

Assessment of cardiac health with echocardiogram and EKG may be prescribed and arrhythmias or abnormalities may require surgical treatment.

As there is no known cure, Loeys–Dietz syndrome is a lifelong condition. Due to the high risk of death from aortic aneurysm rupture, patients should be followed closely to monitor aneurysm formation, which can then be corrected with interventional radiology or vascular surgery.

Previous research in laboratory mice has suggested that the angiotensin II receptor antagonist losartan, which appears to block TGF-beta activity, can slow or halt the formation of aortic aneurysms in Marfan syndrome. A large clinical trial sponsored by the National Institutes of Health is currently underway to explore the use of losartan to prevent aneurysms in Marfan syndrome patients. Both Marfan syndrome and Loeys–Dietz syndrome are associated with increased TGF-beta signaling in the vessel wall. Therefore, losartan also holds promise for the treatment of Loeys–Dietz syndrome. In those patients in which losartan is not halting the growth of the aorta, irbesartan has been shown to work and is currently also being studied and prescribed for some patients with this condition.

If an increased heart rate is present, atenolol is sometimes prescribed to reduce the heart rate to prevent any extra pressure on the tissue of the aorta. Likewise, strenuous physical activity is discouraged in patients, especially weight lifting and contact sports.

Currently there is no cure for PWS. Treatment differs from person to person and depends on the extent and severity of the blood vessels malformations and the degree of correction possible. The treatments can only control for the symptoms and often involve a multidisciplinary care as mentioned in diagnosis. AVMs and AVFs are treated with surgery or with embolization. If there are differences in the legs because of overgrowth in the affected limb, then the patient is referred to an orthopedist. If legs are affected to a minimal degree, then the patient may find heel inserts to be useful as they adjust for the different lengths in the legs and can walk normally.The port-wine stains may be treated by dermatologists. Supportive care is necessary and may include compression garments. These garments are tight-fitting clothing on the affected limb and helps with reducing pain and swelling. This can also help with protecting the limb from bumps and scrapes that cause bleeding. Also again based on the symptoms, the doctors may recommend antibiotics or pain medications.

Surgical care might also be an option for PWS patients. Surgeons may perform debulking procedure in which abnormal and overgrown tissues are removed. If PWS is affecting a foot or leg, the limbs can become quite large. And orthopedic surgeon can operate on the limb to reshape the limb. If the growth of the limb is more than one inch a procedure called epiphysiodesis may be performed. This procedure interrupts the growth of the leg and stops the leg from growing too big.

Other treatment options include: embolization and laser therapy. Embolization includes a substance injected by an interventional radiologists that can help in the elimination of the abnormal connections between the arteries and veins. According to Parkes Weber syndrome—Diagnostic and management paradigms: A systematic review, published in July 2017, reported that embolization alone or in combination with surgical removal of arteriovenous malformations leads to significant clinical improvement. Laser therapy can also help lighten capillary malformations and can speed up the healing process of the bleeding lesions.

Also other specialists are needed for dealing with the progression of the disease such as: physical therapists, occupational therapists and counselors. Physical therapists can help ease the pain and increase the range of movements of the arm or leg that is overgrown. Occupational therapists could help with the development of motor skills impeded by physical problems. The classic port-wine stains may make the patient feel uncomfortable and counselors can help with the psychological and social issues.

PWS is a progressive condition and advances with age. It is dependent on: the extent of the disease and overgrowth, condition of the patient’s heart, if the blood vessels are responsive to treatment, overall health of the patient, tolerance of medications and treatments. Based on these factors the prognosis is fair to good. The deformity and overgrowth tend to progress with time until epiphyseal closure. A lot of medical attention is needed to correct the blood vessels.

Sclerotherapy is a treatment for specific veins and vascular malformations in the affected area. It involves the injection of a chemical into the abnormal veins to cause thickening and obstruction of the targeted vessels. Such treatment may allow normal blood flow to resume. It is a non-surgical medical procedure and is not nearly as invasive as debulking. Ultrasound guided foam sclerotherapy is the state of the art new treatment which could potentially close many large vascular malformations.

Compression therapies are finding more use as of the last ten years. The greatest issue with KTS syndrome is that the blood flow and/or lymph flow may be impeded, and will pool in the affected area. This can cause pain, swelling, inflammations, and in some cases, even ulceration and infection. Among older children and adults, compression garments can be used to alleviate almost all of these, and when combined with elevation of the affected area and proper management, can result in a comfortable lifestyle for the patient without any surgery. Compression garments are also used lately after a debulking procedure to maintain the results of the procedure. For early treatment of infants and toddlers with KTS, custom compression garments are impractical because of the rate of growth. When children may benefit from compression therapies, wraps and lymphatic massage may be used. While compression garments or therapy are not appropriate for everyone, they are relatively cheap (compared to surgery), and have few side-effects. Possible side-effects include a slight risk that the fluids may simply be displaced to an undesirable location (e.g., the groin), or that the compression therapy itself further impedes circulation to the affected extremities.

The treatment of branchio-oto-renal syndrome is done per each affected area (or organ). For example, a person with hearing problems should have appropriate supports and prompt attention for any inflammation of the ear.

A specialist should observe any kidney problems. Surgical repair may be needed depending on the degree of a defect or problem, whether a transplant or dialysis is needed.

Treatment plans will vary depending on the severity of the condition and its evidences in each patient.

Areas that will probably need to be evaluated and assessed include speech, vision, hearing and EEG. Treatment measures may include physical therapy, occupational therapy, Speech therapy, anti-seizure drugs and orthotic devices. Surgery may be needed to assuage spastic motor problems. Various supportive measures such as joint contractures that could prevent complications.

Genetic counseling may also be recommended

Debulking has been the most common treatment for KTS for several decades and while improvements have been made, the procedure is still considered invasive and has several risks associated with it. More effective and less invasive treatment choices now exist for KTS patients and therefore debulking is generally only recommended as a last resort. Debulking operations can result in major deformities and also leave patients with permanent nerve damage.

Mayo Clinic has reported the largest experience in managing KTS with major surgery. In 39 years at Mayo clinic the surgery team evaluated 252 consecutive cases of KTS, of which only 145 (57.5%) could be treated by primary surgery. The immediate success rate for treating varicose veins was only 40%, excision of vascular malformation was possible in 60%, debulking operations in 65%, and correction of bone deformity and limb length correction (epiphysiodesis) had 90% success. All the procedures demonstrated high recurrence rate in the follow-up. Mayo clinic studies demonstrate that primary surgical management of KTS has limitations and non-surgical approaches need to be developed in order to offer a better quality of life for these patients. Major surgery including amputation and debulking surgery does not seem to offer any benefit on a long-term basis.

Once a patient with neurocutaneous melanosis becomes symptomatic, little can be done to improve prognosis as there is no effective treatment for the disorder. Most therapies are designed to treat the symptoms associated with the disorder, mainly those related to hydrocephalus. A ventriculoperitoneal shunt to relieve intracranial pressure is the preferred method.

Chemotherapy and radiotherapy have been shown to be ineffective in cases of neurocutaneous melanosis where malignancy is present. Additionally, due to the total infiltration of the central nervous system by these lesions, surgical resection is not a viable treatment option.

It has been demonstrated that early embryonic, post-zygotic somatic mutations in the NRAS gene are implicated in the pathogenesis of NCM. Recently, experimental treatment with MEK162, a MEK inhibitor, has been tried in a patient with NCM and progressive symptomatic leptomeningeal melanocytosis. Pathological studies with immunohistochemical and Western Blot analyses using Ki67 and pERK antibodies showed a potential effect of MEK inhibiting therapy. Further studies are needed to determine whether MEK inhibitors can effectively target NRAS-mutated symptomatic NCM.

The treatment for Bonnet–Dechaume–Blanc syndrome is controversial due to a lack of consensus on the different therapeutic procedures for treating arteriovenous malformations. The first successful treatment was performed by Morgan et al. They combined intracranial resection, ligation of ophthalmic artery, and selective arterial ligature of the external carotid artery, but the patient did not have retinal vascular malformations.

If lesions are present, they are watched closely for changes in size. Prognosis is best when lesions are less than 3 cm in length. Most complications occur when the lesions are greater than 6 cm in size. Surgical intervention for intracranial lesions has been done successfully. Nonsurgical treatments include embolization, radiation therapy, and continued observation. Arterial vascular malformations may be treated with the cyberknife treatment. Possible treatment for cerebral arterial vascular malformations include stereotactic radiosurgery, endovascular embolization, and microsurgical resection.

When pursuing treatment, it is important to consider the size of the malformations, their locations, and the neurological involvement. Because it is a congenital disorder, there are not preventative steps to take aside from regular follow ups with a doctor to keep an eye on the symptoms so that future complications are avoided.

The use of orthotic bracing, pioneered by Sydney Haje as of 1977, is finding increasing acceptance as an alternative to surgery in select cases of pectus carinatum. In children, teenagers, and young adults who have pectus carinatum and are motivated to avoid surgery, the use of a customized chest-wall brace that applies direct pressure on the protruding area of the chest produces excellent outcomes. Willingness to wear the brace as required is essential for the success of this treatment approach. The brace works in much the same way as orthodontics (braces that correct the alignment of teeth). The brace consists of front and back compression plates that are anchored to aluminum bars. These bars are bound together by a tightening mechanism which varies from brace to brace. This device is easily hidden under clothing and must be worn from 14 to 24 hours a day. The wearing time varies with each brace manufacturer and the managing physicians protocol, which could be based on the severity of the carinatum malformation (mild moderate severe) and if it is symmetric or asymmetric.

Depending on the manufacturer and/or the patient's preference, the brace may be worn on the skin or it may be worn over a body 'sock' or sleeve called a Bracemate, specifically designed to be worn under braces. A physician or orthotist or brace manufacturer's representative can show how to check to see if the brace is in correct position on the chest.

Bracing is becoming more popular over surgery for pectus carinatum, mostly because it eliminates the risks that accompany surgery. The prescribing of bracing as a treatment for pectus carinatum has 'trickled down' from both paediatric and thoracic surgeons to the family physician and pediatricians again due to its lower risks and well-documented very high success results. The pectus carinatum guideline of 2012 of the American Pediatric Surgical Association has stated: "As reconstructive therapy for the compliant pectus [carinatum] malformation, nonoperative compressive orthotic bracing is usually an appropriate first line of therapy as it does not preclude the operative option. For appropriate candidates, orthotic bracing of chest wall malformations can reasonably be expected to prevent worsening of the malformation and often results in a lasting correction of the malformation. Orthotic bracing is often successful in prepubertal children whose chest wall is compliant. Expert opinion suggests that the noncompliant chest wall malformation or significant asymmetry of the pectus carinatum malformation caused by a concomitant excavatum-type malformation may not respond to orthotic bracing."

Regular supervision during the bracing period is required for optimal results. Adjustments may be needed to the brace as the child grows and the pectus improves.

At present, treatment for tetrasomy 18p is symptomatic, meaning that the focus is on treating the signs and symptoms of the conditions as they arise. The Chromosome 18 Clinical Research Center has published a list of recommended screening and evaluations:

The outcome of this disease is dependent on the severity of the cardiac defects. Approximately 1 in 3 children with this diagnosis require shunting for the hydrocephaly that is often a consequence. Some children require extra assistance or therapy for delayed psychomotor and speech development, including hypotonia.

For patients with severe pectus carinatum, surgery may be necessary. However bracing could and may still be the first line of treatment. Some severe cases treated with bracing may result in just enough improvement that patient is happy with the outcome and may not want surgery afterwards.

If bracing should fail for whatever reason then surgery would be the next step. The two most common procedures are the Ravitch technique and the Reverse Nuss procedure.

A modified Ravitch technique uses bioabsorbable material and postoperative bracing, and in some cases a diced rib cartilage graft technique.

The Nuss was developed by Donald Nuss at the Children's Hospital of the King's Daughters in Norfolk, Va. The Nuss is primarily used for Pectus Excavatum, but has recently been revised for use in some cases of PC, primarily when the malformation is symmetrical.

It is suggested that, once diagnosed, individuals be routinely followed by a cardiologist, endocrinologist, dermatologist, and other appropriate specialties as symptoms present.

It is recommended that those with the syndrome who are capable of having children seek genetic counseling before deciding to have children. As the syndrome presents frequently as a "forme fruste" (incomplete, or unusual form) variant, an examination of all family members must be undertaken. As an autosomal dominant trait there is a fifty percent chance with each child that they will also be born with the syndrome. Although fully penetrant, since the syndrome has variable expressivity, one generation may have a mild expression of the syndrome, while the next may be profoundly affected.

Once a decision to have children is made, and the couple conceives, the fetus is monitored during the pregnancy for cardiac evaluation. If a gross cardiac malformation is found, parents receive counseling on continuing with the pregnancy.

Other management is routine care as symptoms present:

1. For those with endocrine issues (low levels of thyrotopin [a pituitary hormone responsible for regulating thyroid hormones], follicle stimulating hormone) drug therapy is recommended.

2. For those who are disturbed by the appearance of lentigines, cryosurgery may be beneficial. Due to the large number of lentigines this may prove time consuming. An alternative treatment with tretinoin or hydroquinone creams may help.

3. Drug therapies for those with cardiac abnormalities, as those abnormalities become severe enough to warrant the use of these therapies. ECG's are mandatory prior to any surgical interventions, due to possible arrythmia.

Current research is focusing on clearly defining the phenotype associated with tetrasomy 18p and identifying which genes cause medical and developmental problems when present in four copies.

According to NIH clinical trials.gov, research on the port-wine stain and its relation to polymorphisms of RASA1 has commenced in November 2010 and expected to end in November 2019. The purpose of the study is to assess how the port-wine stains can lead to complex syndromes such as PWS. Currently there is little knowledge about the epidemiology of the stains and how they progress with the disease. The research is ongoing and the results are yet to be published.

In an another review published in July 2017 (discussed in treatments and prognosis), Banzic et. al. discussed clinical findings that embolization works really well in patients with PWS. Also, embolization along with surgical resection that targets arteriovenous malformations reliably leads to significant clinical improvements.

A baby with a prenatally diagnosed cystic hygroma should be delivered in a major medical center equipped to deal with neonatal complications, such as a neonatal intensive care unit. An obstetrician usually decides the method of delivery. If the cystic hygroma is large, a cesarean section may be performed. After birth, infants with a persistent cystic hygroma must be monitored for airway obstruction. A thin needle may be used to reduce the volume of the cystic hygroma to prevent facial deformities and airway obstruction. Close observation of the baby by a neonatologist after birth is recommended. If resolution of the cystic hygroma does not occur before birth, a pediatric surgeon should be consulted.

Cystic hygromas that develop in the third trimester, after thirty weeks gestation, or in the postnatal period are usually not associated with chromosome abnormalities. There is a chance of recurrence after surgical removal of the cystic hygroma. The chance of recurrence depends on the extent of the cystic hygroma and whether its wall was able to be completely removed.

Treatments for removal of cystic hygroma are surgery or sclerosing agents which include:

- Bleomycin

- Doxycycline

- Ethanol (pure)

- Picibanil (OK-432)

- Sodium tetradecyl sulfate

Treatment for those with lissencephaly is symptomatic and depends on the severity and locations of the brain malformations. Supportive care may be needed to help with comfort and nursing needs. Seizures may be controlled with medication and hydrocephalus may require shunting. If feeding becomes difficult, a gastrostomy tube may be considered.

Management has three components: interventions before delivery, timing and place of delivery, and therapy after delivery.

In some cases, fetal therapy is available for the underlying condition; this may help to limit the severity of pulmonary hypoplasia. In exceptional cases, fetal therapy may include fetal surgery.

A 1992 case report of a baby with a sacrococcygeal teratoma (SCT) reported that the SCT had obstructed the outlet of the urinary bladder causing the bladder to rupture in utero and fill the baby's abdomen with urine (a form of ascites). The outcome was good. The baby had normal kidneys and lungs, leading the authors to conclude that obstruction occurred late in the pregnancy and to suggest that the rupture may have protected the baby from the usual complications of such an obstruction. Subsequent to this report, use of a vesicoamniotic shunting procedure (VASP) has been attempted, with limited success.

Often, a baby with a high risk of pulmonary hypoplasia will have a planned delivery in a specialty hospital such as (in the United States) a tertiary referral hospital with a level 3 neonatal intensive-care unit. The baby may require immediate advanced resuscitation and therapy.

Early delivery may be required in order to rescue the fetus from an underlying condition that is causing pulmonary hypoplasia. However, pulmonary hypoplasia increases the risks associated with preterm birth, because once delivered the baby requires adequate lung capacity to sustain life. The decision whether to deliver early includes a careful assessment of the extent to which delaying delivery may increase or decrease the pulmonary hypoplasia. It is a choice between expectant management and active management. An example is congenital cystic adenomatoid malformation with hydrops; impending heart failure may require a preterm delivery. Severe oligohydramnios of early onset and long duration, as can occur with early preterm rupture of membranes, can cause increasingly severe PH; if delivery is postponed by many weeks, PH can become so severe that it results in neonatal death.

After delivery, most affected babies will require supplemental oxygen. Some severely affected babies may be saved with extracorporeal membrane oxygenation (ECMO). Not all specialty hospitals have ECMO, and ECMO is considered the therapy of last resort for pulmonary insufficiency. An alternative to ECMO is high-frequency oscillatory ventilation.

Prognoses for 3C syndrome vary widely based on the specific constellation of symptoms seen in an individual. Typically, the gravity of the prognosis correlates with the severity of the cardiac abnormalities. For children with less severe cardiac abnormalities, the developmental prognosis depends on the cerebellar abnormalities that are present. Severe cerebellar hypoplasia is associated with growth and speech delays, as well as hypotonia and general growth deficiencies.

In most cases, a fetus with CPAM is closely monitored during pregnancy and the CPAM is removed via surgery after birth. Most babies with a CPAM are born without complication and are monitored during the first few months. Many patients have surgery, typically before their first birthday, because of the risk of recurrent lung infections associated with CPAMs. Some pediatric surgeons can safely remove these lesions using very tiny incisions using minimally invasive surgical techniques (thoracoscopy). However, some CPAM patients live a full life without any complication or incident. It is hypothesized that there are thousands of people living with an undetected CPAM. Through ultrasound testing employed in recent years, many more patients are aware that they live with this condition. Rarely, long standing CPAMs have been reported to become cancerous.

Very large cystic masses might pose a danger during birth because of the airway compression. In this situation, a special surgical type of delivery called the EXIT procedure may be used.

In rare extreme cases, where fetus's heart is in danger, fetal surgery can be performed to remove the CPAM. If non-immune hydrops fetalis develop, there is a near universal mortality of the fetus without intervention. Fetal surgery can improve the chances of survival to 50-60%. Recently, several studies found that a single course of prenatal steroids (betamethasone) may increase survival in hydropic fetuses with microcystic CPAMs to 75-100%. These studies indicate that large microcystic lesions may be treated prenatally without surgical intervention. Large macrocyst lesions may require in utero placement of a Harrison thoracoamniotic shunt.

In itself, NSML is not a life-threatening diagnosis, most people diagnosed with the condition live normal lives. Obstructive cardiomyopathy and other pathologic findings involving the cardiovascular system may be a cause of death in those whose cardiac deformities are profound.